Transmission Woes Continue!

[BillHill93]

P0758 code. I've tested both the a and b solenoid for resistance and get around 23 ohms. I've also tested the 3-2 downshift solenoid, the EPC, and the PWM solenoid. They all check out good. I've checked the harness for continuity all the way from the PCM plug to the solenoids. I've also checked the harness for an external ground. The harness is good. What in the world should I do next to try to figure why I keep getting this code? Transmission will act fine one day and then the next I'll be going down the road and the RPMs will rev up and it slams into gear. Then it will lose 1st and 4th gear all together but then the next time I drive it it's fine. I would think that if the PCM was bad this problem would be more constant. I've read throttle position sensor and vehicle speed sensor but I hate to just throw parts at it. What next? The valve body?

 

[BillHill93]

One other thing also sometimes lose the second gear and just stays in third all the way from a dead stop to as fast as you want to take it.

 

[Jimmyy]

I'm no expert on transmission, but in ohm-ing out the solenoids. All you are doing is making sure the coil is ok. The mechanical function could still be bad.

 

[rockola1971]

Whats your fluid look like? Smell burnt? Have you dropped the pan and taken a look? Checked PCM wiring harness connections for the green crusties?

 

[Joseph Garcia]

@NickTransmissions may be able to provide some perspective on your issues, as he is our resident transmission expert.

 

[BillHill93]

I'm no expert on transmission, but in ohm-ing out the solenoids. All you are doing is making sure the coil is ok. The mechanical function could still be bad.

I suspected that the B solenoid could still be faulty so I did replace it but the problem still persists and I am still getting the same p0758 code intermittently.

 

[BillHill93]

Whats your fluid look like? Smell burnt? Have you dropped the pan and taken a look? Checked PCM wiring harness connections for the green crusties?

I did drop the pan and change the fluid and filter when I first replaced the B solenoid. The fluid was clean. There was no noticeable corrosion on the PCM harness when I checked.

 

[Trackman]

P0758 code. I've tested both the a and b solenoid for resistance and get around 23 ohms. I've also tested the 3-2 downshift solenoid, the EPC, and the PWM solenoid. They all check out good. I've checked the harness for continuity all the way from the PCM plug to the solenoids. I've also checked the harness for an external ground. The harness is good. What in the world should I do next to try to figure why I keep getting this code? Transmission will act fine one day and then the next I'll be going down the road and the RPMs will rev up and it slams into gear. Then it will lose 1st and 4th gear all together but then the next time I drive it it's fine. I would think that if the PCM was bad this problem would be more constant. I've read throttle position sensor and vehicle speed sensor but I hate to just throw parts at it. What next? The valve body?

I replaced my transmission at 248,000. I was out of town - it began to get noisy and wouldn't shift up. Teltale was the smell and appearance of the fluid

 

[rockola1971]

Are you sure it isnt losing 2nd and 4th instead of 1st and 4th? Was tranny pan full of black dust?

 

[BillHill93]

When the issue occurs it loses first, second, and fourth. It will stay in third gear from a complete stop to as fast as I want to take it and never shift. Then the very next day it may very well run all day long without a single issue. When I pulled the pan the tranny fluid was clean and red. The tranny pan was clean also. What would black dust in the tranny pan indicate?